1. Field of the Invention
The present invention relates to a two-axle undercarriage for track-bound transport systems used in freight and passenger traffic. More specifically, the present invention relates to a two-axle undercarriage for inseparable train units carried on the undercarriage frames on which wheel sets are received, wherein at least one of the wheel sets is driven directly by a drive gear.
2. Description of the Related Art
Prior art two-axle undercarriages (which are also referred to as trucks) are known which have compact undercarriage frames on which wheel sets are mounted via wheel set bearings. In a standard swivel truck configuration, a car body is resiliently mounted in a swiveling ring on the swivel truck frame with secondary springs between the swivel truck and the car body. The wheel sets are resiliently mounted in the swivel truck frames using primary springs. The wheel sets are driven by wheel set gears. In these standard swivel trucks, the wheel sets are not steered on curves either actively or passively.
The development of track-bound transport systems in the form of inseparable train units (such as commuter, ICE, and STE trains) has created a need for new undercarriages that support two car bodies at once. Prior art trucks known as Jacobs swivel trucks have the above characteristics for supporting two adjacent car bodies. These trucks are used for supporting streetcars. However, the Jacobs swivel trucks and other conventional designs are complicated, heavy, and therefore expensive, making them undesirable for use on the commuter, ICE, and STE trains, for example.